From 3d66c3be825b1f23dc468944216d2c7e871d1761 Mon Sep 17 00:00:00 2001
From: Zach Loafman <zml@google.com>
Date: Tue, 31 May 2016 17:24:33 -0700
Subject: [PATCH] SSH e2e: Limit to 100 nodes, limit combinatorics

This limits the "for all hosts" to 100 nodes, and also limits the
combinatorial section so that we only do the other SSH command variant
testing on the first host rather than *all* of the hosts. I also
killed one of the variants because it didn't seem to be testing much
important.

Fixes #26600
---
 test/e2e/ssh.go | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/test/e2e/ssh.go b/test/e2e/ssh.go
index 3da59417a2..0a6896b66c 100644
--- a/test/e2e/ssh.go
+++ b/test/e2e/ssh.go
@@ -25,6 +25,8 @@ import (
 	. "github.com/onsi/ginkgo"
 )
 
+const maxNodes = 100
+
 var _ = framework.KubeDescribe("SSH", func() {
 
 	f := framework.NewDefaultFramework("ssh")
@@ -50,17 +52,27 @@ var _ = framework.KubeDescribe("SSH", func() {
 			expectedCode   int
 			expectedError  error
 		}{
-			{`echo "Hello"`, true, "Hello", "", 0, nil},
-			// Same as previous, but useful for test output diagnostics.
+			// Keep this test first - this variant runs on all nodes.
 			{`echo "Hello from $(whoami)@$(hostname)"`, false, "", "", 0, nil},
 			{`echo "foo" | grep "bar"`, true, "", "", 1, nil},
 			{`echo "Out" && echo "Error" >&2 && exit 7`, true, "Out", "Error", 7, nil},
 		}
 
-		// Run commands on all nodes via SSH.
-		for _, testCase := range testCases {
-			By(fmt.Sprintf("SSH'ing to all nodes and running %s", testCase.cmd))
-			for _, host := range hosts {
+		for i, testCase := range testCases {
+			// Only run the first testcase against max 100 nodes. Run
+			// the rest against the first node we find only, since
+			// they're basically testing SSH semantics (and we don't
+			// need to do that against each host in the cluster).
+			nodes := len(hosts)
+			if i > 0 {
+				nodes = 1
+			} else if nodes > maxNodes {
+				nodes = maxNodes
+			}
+			testhosts := hosts[:nodes]
+			By(fmt.Sprintf("SSH'ing to %d nodes and running %s", len(testhosts), testCase.cmd))
+
+			for _, host := range testhosts {
 				result, err := framework.SSH(testCase.cmd, host, framework.TestContext.Provider)
 				stdout, stderr := strings.TrimSpace(result.Stdout), strings.TrimSpace(result.Stderr)
 				if err != testCase.expectedError {